Transient voltage suppressors are used in a variety of electrical systems to prevent high voltage transients from damaging system components. For example, computer systems connect transient voltage suppressors across data and/or power lines to dissipate the energy induced by a transient event such as a noise pulse, a static discharge, or a lightning strike. The transient voltage suppressors break down when a transient voltage exceeds a predetermined level, thereby limiting the voltage on the data and power lines and avoiding component damage. A typical transient voltage suppressor breaks down when a transient voltage exceeds a desired voltage and shunts current which would otherwise flow through other system components and lead to a destructive failure of the system.
Transient voltage suppressors typically have two operational states: a high impedance state or a low impedance state with either a low on-voltage or a high on-voltage. When a fast electrostatic discharge (“ESD”) event occurs, the transient voltage suppressor is designed to clamp in the on-state with a low impedance and a high on-state voltage. When a high energy surge event occurs, the transient voltage suppressor is designed to operate in the on-state with a low impedance and a low on-voltage. A drawback with transient voltage suppressors is that they are optimized for either protection against an electrostatic discharge event or protection against a surge event. For example, a thyristor surge protection device typically provides good surge capability due to the thyristor having an on-state with a low impedance and a low on-voltage. However, as it has a slow response speed, the response to a short electrostatic discharge event has a large overshoot voltage and the inability to clamp at a desired voltage. A Zener diode, on the other hand, protects against electrostatic discharge events but offers poor surge protection due to its high on-voltage.
Accordingly, it would be advantageous to have a transient voltage suppressor capable of protecting against an electrostatic discharge event and a surge event and a method for protecting against an electrostatic discharge event and a surge event. It would be of further advantage for the device and method to be cost efficient to manufacture.